Physical Hazards Noise, Radiation, and Ergonomics

1
Physical Hazards Noise, Radiation, and
Ergonomics
2
NOISE AND ITS EFFECT ON HEARING
3
Introduction

• Definitions
• Biological Process of Hearing
• Two Types of Hearing Loss
• Conductive Hearing Loss
• Sensory Hearing Loss
• Regulatory Levels
• Audiometric Testing
• Measuring Noise

4
Definitions

• Sound
• Composed of Frequency and Intensity
• Frequency or pitch
• Hertz (Hz)
• Intensity or loudness
• Decibels (dBA)
• A doubling of the level of sound is perceived as
  less than double
• Do not trust your ears

5
Biological Process of Hearing

• Outer ear collects sound energy (pressure waves)
• Sound travels down the ear canal to the eardrum
• Sound waves set the eardrum in motion

6
Biological Processes of Hearing

• Inside the cochlea, hair cells bend as waves pass
  by sending pulses via the auditory nerve to the
  brain.
• Sound energy is converted from mechanical
  vibrations to fluid waves to electrical pulses.

7
Two Types of Hearing Loss

• Conductive
• Sensory

8
Conductive Hearing Loss

• Caused by damage to or a malfunction of the outer
  and middle ear
• Some causes
• excessive ear wax
• fluid in the ear
• a torn eardrum
• Colds
• Usually hearing is restored once the cause is
  diagnosed and treated

9
Sensory Hearing Loss

• Caused by damage to or a malfunction of the inner
  ear, auditory nerve, or the brain
• Causes of sensory hearing loss
• Aging, Damage to fetus, Hereditary, Noise,
  Disease, Injury, Drugs

10
Sensory Hearing Loss

• Cannot be corrected medically or surgically
• Hearing loss in the workplace is typically a
  sensory hearing loss

11
Regulatory Levels

• Continuous noise
• 85 dBA, 8 hour TWA - Action Level
• hearing conservation program
• training
• medical monitoring
• 90 dBA, 8 hour TWA - Permissible Exposure Level
  (PEL)
• Wear Ear Plugs
• Impact noise- no exposures above 140 dB shall be
  permitted

12
Audiometric Testing

• Audiogram
• Measures how loud a sound has to be before you
  can hear it
• Comparing current to previous audiograms
• Shows if hearing loss has occurred and at which
  frequencies

13
Measuring Noise

• Sound Level Meter - Instant reading
• grab sample
• Quest 215
• Dosimeter - TWA
• noise exposure is integrated over time
• Quest 7 B
• Du Pont MK 1, 2, 3

14
Types of Hearing Protection Devices

• Foam earplugs
• Earmuffs
• Noise Reduction Rating ( NRR )
• Plugs Muffs
• Take the higher NRR and add 5 dB to it

15
NRR - Noise Reduction Rating

• NRR and choosing an ear plug
• Earmuffs NRR - Subtract 25
• Foam/expanding ear plugs - Subtract 50
• All other plugs - Subtract 75

16
Earplugs

• Advantages
• small and lightweight
• comfortable in hot environments
• easily used with other safety equipment
• Disadvantages
• may become loose and require occasional refitting
• frequently soiled

17
Earmuffs

• Advantages
• fits better for longer periods of time
• Disadvantages
• may fit tight on your head
• uncomfortable in warm environments
• effectiveness is limited to the quality of the
  seal around your ear

18
Inserting foam earplugs properly

• Reach around back of your head
• Gently pull your ear back and up
• Roll the plug into a small diameter
• Insert the plug well into the ear canal
• Hold the plug in place for a few seconds while it
  expands and forms a good seal

19
Hearing Protection

• Make sure that the earmuffs fit snugly around
  your ears
• Use earplugs if you wear glasses, earrings, or
  have facial hair which prevent the earmuffs from
  forming a good seal

20
Caring for Hearing Protection Devices

• Foam Earplugs
• store them in a clean, cool, dry place
• if earplugs become soiled, torn, or stiff,
  discard them and get a new pair
• Earmuffs
• store them in a clean, cool, dry place
• inspect your earmuffs for cracks around the foam
  cups.

21
IONIZING RADIATION
22
OBJECTIVES

• Ionizing Radiation Characteristics
• Radiological Response
• Biological Consequences / Health Effects
• Regulations/Standards
• Radiation Protection/Controls
• Instrumentation
• Types of radiation

23
IONIZING RADIATION DEFINITIONS

• Ionizing Radiation (IR) - Any particles or rays
  given off (radiate) from a source that produces
  ionization
• Ionization - When atoms or molecules become
  charged - unbalanced electron proton ratio.
• Radiation - Refers to the way particles rays
  radiate from their source at speeds up to that of
  light.

24
RADIOLOGICAL RESPONSE

• Spills of Radioactive Material
• Stop the spill,
• Warn others of the spill,
• Isolate the area and
• Minimize exposure to radiation

25
IONIZING RADIATION CHARACTERISTICS

• Common Types of IR
• Alpha
• Beta
• Gamma
• X-rays
• Types of Non-IR
• Radiowaves Microwaves
• Infrared Light
• Visible Light
• Ultrasound
• UV Light

26
IONIZING RADIATION CHARACTERISTICS

• Alpha Radiation (?)
• Physical Characteristics (Helium w/o electrons)
• Weak penetrating power
• Cannot penetrate a sheet of paper
• Internal Hazards

27
IONIZING RADIATION CHARACTERISTICS

• Beta Radiation (?)
• Physical Characteristics (electron)
• External Exposure
• Skin Damage Beta burn
• Method of Ionization
• Annihilation Radiation

28
IONIZING RADIATION CHARACTERISTICS

• Gamma Radiation (?)
• Indirectly ionizing radiation (electromagnetic
  ray - e.g. light)
• Energy bundles - have no charge or mass
• Travels much farther than ? or ? radiation
• Can pass through a body without hitting anything
  or give an atom all or part of its energy.

29
IONIZING RADIATION CHARACTERISTICS

• Units
• Rad Absorbed dose equal to 0.01 Joule/kg in any
  substance.
• Rem Conventional unit for dose equivalent.
• The dose equivalent in rem is equal to the
  absorbed dose in rad multiplied by the quality
  factor.

30
IONIZING RADIATION CHARACTERISTICS

• Radiation dose is expressed in rads
• For ? and ? radiation, 1 rad 1 rem
• For ? radiation, 1 rad 20 rem
• Rem (Rad)(QF)
• Quality Factor (QF) for ? and ? 1
• ?20

31
SOURCES OF EXPOSURE

• Natural Sources (81)
• 55 - Radon
• 8 - Cosmic
• 8 - Terrestrial (coal, crude oil natural gas,
  phosphate rock products, sand, hot springs
  caves)
• 10 - Food Water (i.e., Potassium-40)

32
SOURCES OF EXPOSURE

• Man-made Sources (19)
• 11 - Medical X-ray (?-rays)
• 4 - Nuclear Medical Exposures
• 3 - Consumer Products
• nuclear fallout, nuclear fall cycle radioactive
  waste, hospital radioactive waste, radioactively
  contaminated sites, etc.)

33
SOURCES OF EXPOSURE

• For the U.S. population, average annual total
  effective dose (natural anthropogenic) is
  approximately 360 mrem (0.360 rem).
• For the general public, the exposure limit is 0.1
  rem/year or 2 mrem/hr.

34
BIOLOGICAL CONSEQUENCES / HEALTH EFFECTS

• DNA is the primary target
• Radiation can produce free radicals elsewhere in
  the body that then reacts with DNA
• DNA damage is cumulative
• Cells are most sensitive to radiation damage if
• Have a high mitotic (cell division) rate
• A slow (long) mitotic cycle
• Undifferentiated stem cells
• Exposure to the eyes causes cataract formation.

35
BIOLOGICAL CONSEQUENCES / HEALTH EFFECTS

• Acute Effects Acute Radiation Syndrome (ARS)
• Only seen after whole-body exposures above 100 rad

36
REGULATIONS/STANDARDS

• Worker Limits - Adults Only
• Radiation workers (Fed State)
• 5 rem/year
• Total Effective Dose 5 rem/year

37
TYPES OF RADIATION

• Alpha
• U-238, Pu-238, Pu-239, Ra-226, Po-210, Am-241
• Beta
• H-3, C-14, S-35, Pu-241 (low-energy)
• P-32, Sr-90, I-131 (medium to high energy)
• Also includes partial gamma (I-131)
• Other Gamma (Cs-137, Co-60, Ir-192

38
RADIATION PROTECTION/CONTROLS

• Time
• Exposure increases linearly with an increase in
  the amount of time spent.
• Reduce the time of exposure to a minimum
• ALARA (as low as reasonably achievable)
• Shielding
• Lead and concrete - absorbs the radiation.

39
RADIATION PROTECTION/CONTROLS

• Distance
• Dose rate is inversely proportional to the
  distance squared from the source.
• I1 I2(D2/D1)2
• where I1 is the intensity at a distance D1,
  and
• I2 is the intensity at a distance D2

40
RADIATION PROTECTION/CONTROLS

• PPE
• Prevent contamination of particles on the surface
  of the skin
• The use of shield layers such as eye shield and
  gloves - prevents particles from depositing on
  the body and shields by absorption.

41
INSTRUMENTATION

• Example
• Ludlum 3
• (?, ?, and ?)

42
INSTRUMENTATION

• Example
• Ludlum 19
• (? and x-ray)

43
INSTRUMENTATION

• Example
• SAIC Dosimeters (?)

44
REGULATORY AGENCIES

• California Dept. of Health Services, Radiation
  Branch State Regulatory
• Nuclear Regulatory Commission (NRC)
• Regulates nuclear power plant operations
• Regulates the use of radioactive material in
  research and medical applications
• NRC regulations apply to all types of ionizing
  radiation (IR)
• Sets limits on the total dose of IR above
  background

45
Ergonomics

• A quick overview

46
Ergonomics

• The study of interactions between humans and
  their working environment
• Repetitive motion is one branch

47
Ergonomics

• Examples
• Carpal tunnel syndrome - compressed median nerve
  due to swelling of the tendon sheath
• Prolonged flexing of the wrist - typing
• Tendentious - inflamed tendons due to stress
• Excess motion or stress - frayed, bumpy thick
  tendon
• White Finger - loss of adequate blood supply to
  fingers
• Vibrations, very tight gripping - Jack hammer
• Lower back pain - back stresses especially poor
  lifting
• Bent back, twisting motion, excess weight

48
Ergonomics

• Lifting, protect the back!
• Keep back straight
• Forced to lift with legs
• Exponential increases with leaning over to pick
  up
• Pivot point, lower back
• Think, do not use jerky rapid motion
• Do not twist
• Do not raise above shoulders

49
Ergonomics

• Tools, protect the hand (wrist)
• Keep writs straight with respect to the arm, no
  bending
• Encircled tool should not allow fingers to touch
  palm
• Vary tasks, avoid doing something repetitively
  without breaks
• Keep shoulder relaxed and elbow at the side of
  the body

50
Ergonomics

• Universal Key Points
• Avoid sustained repetitive motions
• Flex joints minimally
• Work between shoulder and elbow height
• Use good illumination
• Do only what is comfortable, not pushing to the
  limits
• Use good posture

51
QUESTIONS?